It was a cold and rainy day in London (when isn't it, har, har?) when the four Fabs arrived at Abbey Road to begin the day's session, having recently put the finishing touches on songs "Strawberry Fields Forever" and "Penny Lane".
This song was to be their most ambitious and musically-challenging track because, as they began recording the tune, they hadn't yet arrived at a proper arrangement, much less how to properly connect the two halves of the song - Lennon's verses and McCartney's bridge section - together.
Recording began with just John Lennon playing a guitar and singing a rough lead vocal. Says George Martin in a 2007 interview for Q Magazine:
"John's voice - which he hated - was the kind of thing that would send shivers down your spine. If you hear those opening chords with the guitar and piano, and then his voice comes in, 'I heard the news today, oh boy' It's just so evocative of that time. He always played his songs to me on the guitar and I would sit on a stool as he strummed. The orchestral section was Paul's idea. We put two pieces of songs together that weren't connected in any way. Then we had that 24-bars-of-nothing in between.
I had to write a score, but in the climax, I gave each instrument different little way points at each bar, so they would know roughly where they should be when they were sliding up. Just so they didn't reach the climax too quickly. With A Day In The Life, I wondered whether we were losing our audience and I was scared. But I stopped being scared when I played it to the head of Capitol Records in America and he was gob smacked. He said, That's fantastic. And of course, it was."
The song would take a month to finish, with a symphony orchestra being brought in to create the now-iconic orchestra swirl that connects the two parts of the song together.
The final version, of course, remains one of the most intriguing and beguiling songs in the Beatles' catalog, if not all of rock history, with fans and historians both hypothesizing as to which Beatle sang the "ahhh's".